When Tashkent's central districts were rocked by series of bombings 10 years ago, terrorism was not a word commonly equated with Central Asia.

But history has since treated the bombings not as isolated incidents, but as a watershed event that heralded the arrival of terrorism to the region.

Today, the region features a number of home-grown "suspect" and "banned" groups, some with a proven record of violence, and some which have spread their operations outside Central Asia. At the same time, the region has seen the arrival of groups from abroad attracted by the vacuum left by the fall of the Soviet Union.

The group suspected of carrying out the Tashkent bombings, which killed 16 people, is now well-known as the Islamic Movement of Uzbekistan (IMU). But at the time, there was no such group, as the IMU took its name in the summer months that followed the February 16, 1999, attacks.

The IMU's leader was Juma Namangani, a soldier in the Soviet Army in Afghanistan who later fought on the side of Tajikistan's opposition in that country's 1992-97 civil war. Prior to the Tashkent bombings, he allegedly headed of one of the major drug-trafficking routes between northern Afghanistan and southern Kyrgyzstan.

In early 2001, noted author Ahmad Rashid said IMU leader Namangani's "principle aim is still the Ferghana Valley," which runs through Uzbekistan, Kyrgyzstan, and Tajikistan, "and toppling [Uzbek President Islam] Karimov because he is seeing a kind of domino effect."

"If Karimov is toppled and parts of Ferghana are occupied by the Islamic Movement, then that will create a domino effect in Central Asia, given that all the other regimes are probably in a much weaker position than Uzbekistan's regime," Rashid added.

The Tashkent bombings were pinned on the IMU in the summer of 1999 when the group announced their arrival after descending from Tajikistan's mountains and clashing with Kyrgyzstan's army in an attempt to return to Uzbekistan. The IMU did not reach Uzbekistan that summer. But in the summer of 2000 it did cross into southeastern Uzbekistan to bring its fight to southern Kyrgyzstan as well.

After 9/11

The IMU staged one small attack in summer 2001 but the bulk of the group's fighters were elsewhere, in Afghanistan, where they were joined with Taliban and Al-Qaeda forces in fighting the holdout opposition that controlled about 5 percent of Afghanistan as the summer of 2001 ended.

The IMU's status as a relative unknown changed forever with the September 11, 2001, attacks in the United States.

As the U.S.-led campaign to depose the Taliban and oust Al-Qaeda from Afghanistan was being prepared, Martha Olcott of the Washington-based Carnegie Endowment for International Peace said that the IMU would be among the groups targeted.

Olcott said that the IMU "has been linked to Osama bin Laden. The president [Bush] introduced it to the American people as a target. So I think we are unlikely to leave the region without it [IMU] destroyed, as well as the terrorist camps of bin Laden."

The IMU was badly crippled in fighting in November 2001 near the Afghan city of Konduz, and Namangani was reportedly killed. The group split and fled, some to Central Asia, others to Pakistan's tribal areas. The IMU has never reemerged to stage the types of raids it did in 1999 and 2000, but it still garners considerable attention.

The IMU most recently made headlines through its link to video threats against Germany, and for being targeted by unmanned drone attacks in Pakistan's South Waziristan region.

Several attacks in Central Asia in recent years have been credited to the IMU, including a bombing outside Tajikistan's Emergency Situations Ministry in June 2005 and attacks on Tajik and Kyrgyz border posts in May 2006. In Pakistan's restive tribal areas bordering Afghanistan, IMU fighters continue to participate in battles. Exporting Terror

The IMU is also believed to have spawned various other groups, including the Islamic Movement of Turkestan, which is accused of having grand designs on the lands from China's Xinjiang Uyghur Autonomous Region, home to the Muslim Uyghurs, all the way to the Caspian Sea.

Another offshoot has made its way to the heart of Europe. The Islamic Jihad Union (IJU) was among the groups that claimed responsibility for attacks in Tashkent and Bukhara in late March-early April 2004 that left 47 people dead, most of them attackers and police. Not much attention was paid to their claim at the time, as they were then unknown, leading the Uzbek government to search for other, better-known, suspects.

But the IJU resurfaced in 2007 when German police arrested three men with alleged ties to the organization for plotting domestic terrorist attacks against the U.S. military base at Ramstein and the U.S. and Uzbek consulates. German police arrested three more suspected IJU members of the group in September 2008. German and Uzbek authorities have been in frequent contact since the first arrests, indicating German officials see a link that goes back to Uzbekistan.

Hizb ut-Tahrir literature is regularly seen in much of the region.

Some groups, including Bayat, in Tajikistan, tend to confine their activities to small areas. Arguably the most violent of any of the groups in Central Asia, Bayat has only operated in the Isfara region of northern Tajikistan. The group killed a Baptist pastor there in January 2004 and later attacked Muslim clerics suspected of being loyal to the government and burned several of their mosques.

Tajik authorities have arrested scores of Bayat followers since, including some of the group's leaders. Bayat's activities have decreased significantly in the past few years but in mid-2006, Tajikistan's Interior Ministry warned that Bayat was spreading into neighboring countries. Later that year the Interior Ministry said it discovered a bunker in the Isfara region belonging to Bayat.Importing Radical Islam

Numerous groups from outside the region are believed to have sent missionaries into Central Asia after the collapse of the Soviet Union. The most notable today are Hizb ut-Tahrir, the Salafi movement, and Tabligi Jamaat.

Salafism was banned in Tajikistan at the start of this year. The movement claims to follow a strict and pure form of Islam, but Tajik clerics say the Salafis' radical stance is similar to that of the Taliban in Afghanistan. Tajikistan's Interior Ministry has been expressing concern about the group since early 2006, but there was never any clear evidence the group engaged in violence.

There have been very different reports about Salafism in Kazakhstan. In late 2007, security officials released information that in April that year they had foiled plans by a jihadist wing of Salafis to stage attacks in southern Kazakhstan during a visit by the country's president. The plans included bombing the regional building of the Committee for National Security (KNB) and killing KNB employees and their families.

Hizb ut-Tahrir is the most widespread group in the region, with supporters in Central Asia believed to number in the tens of thousands. There have been reports of arrests of Hizb ut-Tahrir supporters in all of the Central Asian countries except Turkmenistan.

"First of all, it's a political organization primarily. And perhaps secondarily, a religious one, although it's certainly on their agenda to promote the revival of religion and ultimately to achieve a caliphate -- that is an Islamic state -- across the region," says John Schoeberlein, director of Harvard University's Central Asia program.

"The goal is to work in the underground in opposition to the existing governments and ultimately to eliminate them," he adds. "It's certainly the most influential, most widely popular political Islamic group in Central Asia."

The Uzbek blamed the violence in Andijon on Islamic terror, though many of its claims are disputed.

Some of the Central Asian governments, particularly the Uzbek government, have tried to tie Hizb ut-Tahrir to acts of violence in the region. But none have ever been able to provide compelling proof that Hizb ut-Tahrir supporters have been involved in any of the region's violence.

Still, comments like these from a Hizb ut-Tahrir supporter in 2002 give some indication of why Central Asian governments are worried about the group: "We are opponents of the democratic system. We are not against individuals if they embrace Islam and return to Allah. If a person wants to live according to Shari'a [Islamic law], he is our brother. If he wants democracy and to live by the laws of the 'kufr' [nonbelievers], he is then our enemy. Kufr are our enemies. If [former Kyrgyz President Askar] Akaev willingly accepts Islam, and if he imposes Islamic laws, he can sit on his throne."

The presence of supporters of Tabligi Jamaat has been reported in Kazakhstan recently. One of the first times the group was mentioned was in late 2002, when Kazakh security forces detained 34 Uzbek and Kazakh citizens for doing missionary work for Tabligi Jamaat.Central Asian Scapegoats?

There had been much talk of a group called Jamoat after the investigation into the 2004 attacks in Bukhara and Tashkent led to people in both Uzbekistan and Kazakhstan. The Uzbek government preferred to blame the attacks on the IMU, despite the fact that its new leader, Tohir Yuldash, and at least several hundred IMU fighters had been reported in Pakistan's tribal area just days before the attacks in Uzbekistan.

Olivier Roy, a noted author on Central Asian affairs, told RFE/RL at the time that it was "quite unlikely" that the IMU had the "institutional" capacity to order attacks in Uzbekistan from camps in Pakistan.

It has often been unclear precisely who reported terrorists or extremists are. In the case of the 2005 violence in Andijon, the Uzbek government blamed supporters of Akramiya, a localized group centered, allegedly, around a man jailed in Uzbekistan. The group allegedly entered Uzbekistan from Kyrgyzstan, ambushed a police station, and attacked a prison before briefly taking over administrative buildings in Andijon. Scores of people were killed, maybe hundreds, when Uzbek forces recaptured the city.

Kazakh authorities have detained people in Shambyl Province's Makpal Gorge for belonging to radical Islamic groups that went unnamed.

Last September's shoot-out in Turkmenistan's capital, Ashgabat, has still not been fully explained. Initial reports claimed security forces were clashing with Islamic extremists but later reports said they were drug traffickers.

Central Asian governments have more often than not resorted to using a heavy hand to deal with these groups. Some analysts have called this counterproductive, saying it only forces moderate Islamic groups to become radical and helps radical groups recruit new members.

And though many of these groups have members in several Central Asian countries, there has been at best sporadic cooperation in trying to counter such organizations. Faced with outbreaks of terrorism, the Central Asian governments have been more likely to criticize one another even as they try to restore order at home.